Underreaming impact drill



a l J. A. ZUBLIN UNDERREAMING IMPACT DRILL Filed Maich 20, 1923 2 Sheets-Sheet l www ATTORNEY.

i 2 u jam my 9 7 J. A. zuBLlN UNDERREAMING MPACT DRILL 2 Sheets-Sheet 2 Filed March 20. 1925 IIS/z/ENTOR.v y@ Kga/4,',

Patented Jan. 11, 1927.

UNITED STATES :roma A. zUBLrN, or Los ANGELES, cALu'onNIA.

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Application mega maren 2o, ma. serial No. 826,312.

This invention relates to impact drills,

and is particularly directed to certain improvements upon drills ofthe general Character disclosed in my co-pending application 5 Sr. No. 580,645, which has becomePat'ent No. 1,587,265, issued June 1, 1926, said drills being adapted initially to take a twisting grip upon material cut, and then to rotate during the completion of an impact stroke.

It is an object of the present invention to provide a non-collapsible underreaming drill 'of the impact type, which has a positive turning action during a part only of each impact stroke.

A further object is to provide a rigid one piece drill which is capable of being lowered through a well casing and of being subsequently reciprocated to form a bore of a diameter greater than that of the casing,

the drill having an inherent turning action during a part only of each impact stroke. Another object is to provide a drill of the above character in which the cutting end is offset or eccentrically disposed relative to the drill shank or body so that upon rotation of the drill during its reciprocation,

the eccentric cutting end will be bodily ro-I tated about the axis of the shank and drill a hole enlarged by approximately twice the so amount of oliset or eccentricity, the bit be ing automatically maintained in arr underl reamind position.

Another object is to provide a drill which is so formed as to have a positive turning action during each impact stroke, and. which is rovided with a cutting or boring end'of a oring radius greater than the internal radius of the casing or bore through which the drill is to be lowered, with said end` lf eccentrically disposed relative to the shank I Y 4set or eccentrically disposed relative to the of the drill, whereby, when the drill is attached to a tool-string and lowered through a. well 'casing or bore, the'drill shank and` the tool-string will be disposed to one side of the casing axis or closely adjacent one side wall of the casing, and when belowvthe casing the heavier shank and toolestring will, through gravity influence, become een#A tered inthe well bore so that upon reciprooa'tion of the drill with 'its resulting turning action, the lighter oli'set or eccentric cutting end will swing bodily about the axis of the The shank 4 of the drillis axially ali l heavier shank and tool-strinI and eect the boring of an enlarged or un erreamed hole.- Various other obJects and advantages will be more fully apparent from the following description of the accompanyinv drawings which form a part of this disc osure and which illustrate a preferred Iform of embodiment of the invention.

Of ,the drawingsz' Fig. l is a longitudinal section through a well bore yand casing, showing the drlll attached to the lower end of a tool-string and being lowered through the casing.y

Fig. 2 is a similar section showing` the drill in" position for drilling.

Fig. 3 is a plan section on line 3 3 of Fig. l.

Fig. 4 is a plan section on line 4-4 of Fig. 2.

Fig-5 is a bottom plan view of the drill.

Fig. .6 isan elevation of the drill, looking towards the right in Fig. 2.

Fig. 7 is a plan section on line 7-7 of Fig. 6.

Fig. 8 is a perspective view of the cutting end of the drill.

In the drawings, 1 designates a well bore down which a casing 2 is lowered from time to time during the drilling of the well, and in the well known manner, and 3 designates the lower end of a tool-string to ,which the drill is attached, it being understood that the tool string is reciprocated during drilling in the usual manner and by the usual means employed in cable tool drilling. d

with the tool-string and is provided with a V-screw threaded tapered in 5 for attachment thereto, but the drill is istinctive inthat its lower body portion and cutting end are olfshank `4, the degree of this eccentricity being clearly shown by the broken center line 6 -fthe cutting end 'being to one side of the broken center line 7 of the drill shank 4 and the tool string 3. Y

The effect of this offset or eccentric disosition of the cutting end of the drill will he later explained, it being thought advisable to irst describe briefly the construction and action of the cutting end itself.

The portion 8, whichmay be termed the body of the drill, has a cross-sectional conj tour of the form shown in section in F ig. 7,

this form providing opposite vertical edge surfaces 9, adjacent angled corner surfaces 10, and opposed longitudinal flutes 11, with the walls of the flutes angled outwardly to meet the edges of the corner surfaces. 10.

A. transverse cutting blade 12 projects downwardly from the body portion 8 and is diagonally disposed relative to the disposition of the Hates 11, that is, the blade extends diagonally across the lower end of the drill from one angled corner surface 10 to the diametrically opposite angled corner surface 10, thus defining two diagonally opposite shoulders 18 on opposite'sides of the blade.

rlhe respective sh )ulders 13 are angled upwardly from the base of the cutting blade 12 to their outer points 14, and function during the latter part of each impact stroke as impact or crushing shoulders to crush the loosened material and as reaming cutters for reaming the well bore to size.

`With the impact shoulders 13 angled upf wardly from the base of the blade 12 to their outer points 14 and the reaming edges 15 dressed out to gaugc,said remaining edges 15 will be angled circularly from the base of the blade backwardly and upwardly to the1 respectivo rearward points 14, the terms forward and rearward as used being relative to the direction of rotation of the drill, and as the respective shoulders-13 are on opposite sides of the vertical axis of the body 8 and are angled in opposite directions from the blade, it will be understood that upon each down stroke, the shoulders will have a screw like action upon the circulation water and material in the bore and will effect a partial rotation of the drill in the direction of the arrows 16 in the several views.

vln a drilling operation, the transverse cut-V ting blade 12 whose longer horizontal diameterfis shown as equal to the horizontal diameter of the drill cuts or loosens the formation ahead of the reaming and crushing shoulders 18, thereby assuming a major portion of the work and the drill by its turning movements causes said blade to strike the bottom of the hole at more or less regular circularly spaced intervals this permitting the circulating water to freely enter each newly formed cut. The shoulders 13 crush the pieces of broken loose material, forcing such material into the flutes 11, and in loose or unconsolidated formation partly back into the wall of the bore thereby reinforcing and packing such wall to reduce danger of caving thereof. This crushing action does not pack the material at the bottom of the bore for the reason that the shoulders 13 being angled upwardly exert their crushing action towards the side walls.

The reaming edges '15 do only a slight retenes amount of work in trueing the bore to gauge and for this reason have an exceptionally long effective life before redressing thereof is necessary.

rll`his provides a drill vwhich upon each impact stroke has a rapid turning action, and if it is rigidly connected with the tool-string it will be obvious that the entire tool-string is likewise rotated.

Now considering the standard tool-string consisting of bit, stem, jars, and socket all axially aligned, it will easily be understood that any rotation thereof will be the same as the rotating of a straight shaft, but in the present instance we have a drill or bit whose lower or cutting end is offset or eccentric-to the tool-string, therefore, upon rotation of the tool-string the body of heavier weight, in this instance the heavy stem, jars and socket, will practically maintain their axial disposition7 and the lighter offset or eccentrically disposed cutting end will turn not about its own individual axis but bodily around the axis of the heavier toolstring much in the same manner as a crank turns about its shaft.

From the above it will be evident that we have a bit or drill which although its blade may enter without initial rotation has a positive turning action during the latter part of each impact stroke, and which has an off.- sct or ecccntrically disposed cutting end, whereby the turning action willV cause 4the lighter cutting end to be bodily rotated about the axis of the heavier shank and tool-string and form a bore enlarged by approximately twice the degree of eccentricity, that is, an eccentricity of one inch will result in a bore enlarged by substantially two inches.

By reference to Figs. 1 and 3, it will be seen that the cutting end of the drill is dressed out to a gauge which will allow the drill to conveniently pass through the casing, and that in lowering the drill and toolstring down the casing the shank 4 of the drill and consequently the tool-string, will occupy a position to one side of the axis of the casing. y

After the drill is lowered to a position below the casing, it will by gravity influence become centered so that the shank and the tool-string will be in approximate alignment with the axis of the casing, as shown* in Figs. 2 and 4. lVhen the drill is then rcciprocated, and considering the fact that it is forced to rotate during each down or iin'l pact stroke, it will be evident that the lighter cutting end of the drill will bodily rotate about the heavier shank and tool-string, and that asa result the drill will in one operation bore an enlarged or underreamed hole of a size sufficient to permit a lowering of the well casing without first having to perform a separate underreaming operation.

It will be pointed out that the functions inherent inthe drillof the present invention are in a large measure-deplendent upon the I do not wish to limit the invention in this. regard, for it is susceptible of embodiment in various other forms, all coming within the scope of the following claims.

' I claim:

l. An underreaming impact drill having a shank, and a diametral cutting end at the bot-tom of said drill and offset relatively to the shank and provided with means to effeet a rotation of the drill during a part only of each impact stroke.

2. An underreaming impact drill having a shank, and a cutting end at the bottom of said drill and eccentrically disposed relatively to the shank and formed to provide a transverse cutting blade and diagonally op- Eosite shoulders on opposite sides of the lade, the shoulders being angled to effect a rotation of the drill during a part only of each impact stroke.

3. A non-collapsible underreaming impact drill having a shank adapted for attachment to a tool-string, and a cutting end at the bottom of said drill and eccentrically disposed relatively to the shank and formed to provide a depending cutting blade and impact shoulders oppositely angled to effect a rotation of the drill duringa part only of each impact stroke.

4. An'underreaming impact drill adapted to rotate during a part only of its impact stroke and having a shank, and ai body eccentrically disposed relatively thereto, the body having at its lower end transverse depending cutting blade and formed to provide two diametrically opposite impact shoulders at the base of the blade, one extending outwardly from the end portion of one side wall of the blade and the other extending outwardly from the opposite end portion-of the opposite side wall of the blade, with both shoulders angled upwardly and rearwardly relative to the direction of rotation.

5. An underreaming impact drill adapted to rotate during its impact stroke and having a shank, and a body eccentrically disposed relative thereto, the. body being' provided with flutes on opposite sides thereof and having a transverse depending cutting blade between the flutes, and formed at the base of the blade to provide an impact shoulder extending outwardly from one side wall of the blade on one side of the adjacent flute, and an opposite impactshoulder extending outwardly from the opposite side wall of the blade on the opposite side of the opposite flute, both shoulders being angled upwardly and rearwardly relative to the direction of rotation.

6. An underreaming impact drill adapted to rotate during its impact stroke and having a shank, and a body eccentrically disposed relative thereto, the body being provided with flutes on opposite sides thereof and having a.' transverse depending cutting blade between the flutes, and formed at the baseof the blade to provide two opposed impact shoulders on opposite sides of the blade angled upwardly and rearwardly relative to the direction of rotation, the blade being diagonally disposed relative to the disposition of the iiutes so that approximately the entire area oteach shoulder is positioned to one side of the adjacent flute.

7 A11 underreaming impact drill ada ted to rotate during its impact stroke and ing a shank, and a body eccentrically disposed relative thereto, the body being provided with iutes on opposite sides thereof and with a transverse depending cutting blade between the tintes and diagonally disposed relative to the disposition of thetintes, and formed at the base of the blade to provide two diametrically opposited impact shoulders on opposite sides of the blade and on opposite sides of the respective adjacent flutes, the shoulders being diagonally disposed relative to the transverse plane of the blade and angled upwardly and rearwardly relative to the direction of rotation.

8. An underreaming impact drill adapted to rotate during its impact stroke and having a shank, and a body eccentrically disposed relative thereto, the body having a transverse depending cutting blade and formed at the base of the blade to provide two diagonally opposite impactshoulders on opposite sides of the blade, each shoulder being angled upwardly and rearwardly relative to the direction of rotation, and at least one of the shoulders being dressed out to gauge to fuiictionas a reaming cutter.

9. An underreaming impact drill adapted to rotate during its impact stroke and having a shank and a bod'y ecentrically disposed relative thereto, the body having a transverse depending cutting blade and formed at the base ot' the blade to provide two diagonally opposite impact surfaces on opposite sides of the blade, each shoulder being angled upwardly and rearwardly relative to the direction of rotation with its outer edge angled circumferentially and dressed.

:it itsi lower end a blade provided with means www@ p'ci 'l drill bit having at its lower end n blade Whose longer horizontal diameter 10 aiming it to rotate whil(l nmintnined by equals the maximum horizontal diminetei` of gi'nvityin :in nndei'i'enniin;r position, lli@ said drill.

lioi-izoi'itnl diameter of Suid blade being tlie Signed at Los Angeles, California, this esimo as the innxinnnn horizontal diameter lh day of March, 1923.

-lsaid drill.

' i JOHN A. ZUBLIN.

l2. An underieziminff. self-rotating iinll. An nnderieaming impact drill having 

